Chris Polly, Fermilablss.fnal.gov/conf2/C090720/wg4_polly_newfnalg2exp.pdf · Chris Polly, NuFact, 22 July 2009 5 Current a (exp-thy) hinting at new physics? K. Hagiwara, A.D. Martin,

Chris Polly, NuFact, 22 July 2009 1

Bringing Muon g-2 to FermilabBringing Muon g-2 to Fermilab

Chris Polly, FermilabChris Polly, Fermilab


Why measure the muon magnetic moment?

For a point like Dirac particle g=2...deviations enter via quantum fluctuations

QED Electroweak Hadronic


Why measure the muon magnetic moment?

For a point like Dirac particle g=2...deviations enter via quantum fluctuations

Provides an EXTREMELY SENSITIVE and GENERAL probe of higher mass exchanges

QED Electroweak

+ ???

*Makes up for x1000 better precision of ae

Hadronic


Current a(exp-thy) hinting at new physics?

K. Hagiwara, A.D. Martin, Daisuke Nomura, T. Teubner

Other modern a(exp-thy) evaluations, units of a in 10-11

HMNT (2008) 276 81 (3.4)

DEHZ (2006) 277 84 (3.3)

Jeger. (2008) 267 96 (2.8)

Most recent evaluation by De Rafael (arXiv:0809.3025)

Leads to a a(exp-thy) evaluation, units of a in 10-11

Rafael (2008) 295 81 (3.6)

BNL a(exp) = 116 592 080(63) x 10-11

Theory evaluation stable!


Current a(exp-thy) hinting at new physics?

K. Hagiwara, A.D. Martin, Daisuke Nomura, T. Teubner

Outside of oscillations, arguably the most compelling evidence for BSM physics in the last decade!!!

Other modern a(exp-thy) evaluations, units of a in 10-11

HMNT (2008) 276 81 (3.4)

DEHZ (2006) 277 84 (3.3)

Jeger. (2008) 267 96 (2.8)

Most recent evaluation by De Rafael (arXiv:0809.3025)

Leads to a a(exp-thy) evaluation, units of a in 10-11

Rafael (2008) 295 81 (3.6)

BNL a(exp) = 116 592 080(63) x 10-11

Theory evaluation stable!


Model Version

Expt

a(

exp-t

hy)

x 1

011

This 3 difference particularly relevant in LHC era..

Imagine SUSY is proven to be reality...

Huge resolving power between various scenarios

Current discrepancy consistent with more common Snowmass points

But which model is correct?

Kaluza-Klein states or MSSM?

a(UED) = -13 x 10-11

a(MSSM) = 298 x 10-11

tan hard at LHC, g-2 must stronger

Lots of other models (besides SUSY) continually confronted by g-2...general

Marchetti, Mertens, Nierste, Stockinger (0808.1530)


FNAL proposal to reduce a(exp) by 4-5, same technique

Stat error dominates! Combined total error 0.54ppm, new goal 0.14ppm


First step...20x more stored muons

Brookhaven AGS: Only possible to get factor of 4 in luminosity over original experiment

$13M in BNL-specific costs to run HE fast-extracted protons

Still need to build accumulator ring to get longer decay path, and other upgrades

J-PARC: Can get factor of 20 at projected lumin.

Interferes with (and kaon) program

Clever idea for future g-2 experiment, see prior talk by Naohito Saito

Fermilab: Beam is plentiful (even pre-Project X).

Runs in parallel with MI program

Nice synergy with mu2e and intensity frontier (IF) program being pursued at FNAL

Results in 5 years, early flagship result for IF


The baseline configuration at FNAL

Use Booster bunches available after 15Hz upgrade...no NOvA interference

Rebunch into 4 'bunchlets' in Recycler (potentially useful for mu2e)

Reuse AP0 target area to produce pions

One loop around debuncher gives 800 m -> decay line

Muons brought up to new surface building on MI side of AP0


One problem...the ring's in Brookhaven!!!

Ring built in 12 sections and can be disassembled. Moving 600 tons of steel in yoke and subsytems 'easy' part

Monolithic 14 m diameter cryostats with superconducting coils inside are a little harder


No problem

Transport coils to and from barge via Sikorsky aircrane

Ship through St Lawrence -> Great Lakes -> Calumet SAG

Subsystems can be transported overland, but probably more cost effective to ship steel on barge as well.


Load not an issue and coils moved before

Erickson Aircrane: Sikorsky S-64F specs

Rotor diameter 22.7 meters...compare to 14.5 meter diameter coils

Max hook weight 12.5 tons...compare to max coil weight of 8 tons

Craned in past with lifting fixture shown

Total in helicopter opearations <$380k


Other ideas to increase stored muons (and reduce errors)

Lengthen decay channel

Open inflector

Better kicker waveform

Goal: total sys error < 0.1 ppm

Many other ideas to reduce errors, but more work needed

Monitor muons with chambers in vacuum

Reduce pileup syst. with lower threshold


Spatial resolution of pileup

Segmented W-SciFi calorimeter to provide ~35 cells of spatial resolution

Consistent with Moliere radius

BNL calorimeters had no segmentation

First block constructed at Urbana and tested at FNAL MTest facility

R&D continues on SiPM readout

400-500 MHz WFDs to be mounted directly on each detector station


Switch gears and talk about theory prospects

Theory error dominated by QCD piece

Common to divide hadronic loops into 3 categories...

a(had,LO) = 6908 44

a(had,HO) = -98 1

a(had,LBL) = 105 26*Courtesy E. De Rafael, arXiv 0809.3025

( ) ( )( )muons

hadrons

→σ→σ= −+

−+

ee

eesR

( ) ( )∫∝∞

µπm

,had sRssK

dsa2

1


Reducing a(had,LO) requires precision e+e- -> hadronsExperiments have reduced error such that 2 region no longer dominates error

Data from Novosibirsk (CMD2 and SND)

All modes but 2 luminosity measured using Bhabha scattering

For 2, ratio N(2)/N(ee), form factor to 1-2%

*Courtesy V. Logashenko, Tau 2008

contribution error2(from F. Jegerlehner)


KLOE has pioneered use of ISR for a

Unbelievable statistical precision

KLOE agrees with direct CMD2 & SND

weighted contribution


New facility VEPP-2000 and upgraded detectors

VEPP-2000

SND2000 CMD3

Lots of machine and detector upgrades in Novosibirsk

Factor of 10-100 in stats, > 10 from luminosity alone

Energy extend range up to 2 GeV

Experiments start in 2009!!!

Not to mention more ISR results coming from KLOE and Babar


Overall projection of where we will be in ~5 years■ Present:

◆ Experimental uncertainty = 63 x 10-11 (0.54 ppm) 0.46 ppm statistical 0.28 ppm systematic

◆ Theory uncertainty = 51 x 10-11 (0.44 ppm)

Leads to ∆aµ(Expt – Thy) = 295 ± 81 x 10-11 3.6 σ

■ Goal for FNAL experiment:

◆ Experimental uncertainty: 63 16 x 10-11

0.1 ppm statistical 21x the BNL events 0.1 ppm systematic overall

● 0.07 ppm field 0.17 0.07● 0.07 ppm ωa 0.21 0.07

◆ Theory uncertainty: 51 30 x 10-11

(If xx remains 295, the deviation from zero would be close to 9σ)

Future: ∆aµ(Expt – Thy) = xx ± 34 x 10-11


In conclusion...

The very successful muon g-2 program at BNL ended with a statistics-limited >3 discrepancy in a(exp-thy)

Moving g-2 ring to FNAL will give necessary x20 luminosity... very complimentary to BSM probed by mu2e

With modest syst errors improvements, reduce a(exp) from 0.56 ppm to 0.14ppm...huge resolving power for BSM theories

Theoretical error currently limited by a(had,LO), and should improve significantly after ISR and VEPP-2000

Not discussed here, parasitic improvement in muon EDM limit by two orders of magnitude also part of proposal.

Status

Collaboration presented proposal to PAC in March

PAC response very positive, recommended pursuing this as part of FNAL program at reduced proposal cost

Independent cost review finalized in May and real resources allocated at FNAL to optimize project and report back to PAC this November

THANK YOU!!!


Backup slides


Theory stable for decades (modulo 1 sign error)

*Courtesy F. Jergerlehner, arXiv:0902.3360


What if the error was in (s)?

Passera et al“where” to make the cross section change

Higgs allowed


Improvements in B field determination


What about the ?

Belle data in tension with ALEPH

Direct prediction for N(2) off by 4.5

Original proponents think not usable until these discrepancies understood

*Courtesy M. Davier, et al., arXiv 0906.5443


data systematically higher in 0.6-1.0 GeV

Same region where region where Belle data in tension with ALEPH

*Courtesy M. Davier, et al., arXiv 0906.5443


Uses 0.5 mm thick tungsten plates without grooves, interleaved with 0.5 mm fiber ribbons

Fabrication test calorimeter block

Stacking Gluing

Machining Polished end

Documents

Chris Polly, Fermilablss.fnal.gov/conf2/C090720/wg4_polly_newfnalg2exp.pdf · Chris Polly, NuFact, 22 July 2009 5 Current a (exp-thy) hinting at new physics? K. Hagiwara, A.D. Martin,